For anyone having this issue, you can either update MobArena to the latest Bleeding Dev build OR you can update RangedWolves to 0.8.7 - OldMA.

For anyone else having this issue, please refer to my first post here. The link provided is where the Bleeding Development build of MobArena is. It is 1.0.1 compatible, but since it is a Dev version, it is not without it's bugs. Report any bugs (preferably to the correct plugin lol) found please!

Also, if for whatever reason you do not want to try the latest Dev version of MobArena, the last version of RangedWolves that should still work is v0.8.5 (see the files tab for all the old files)